CHARLOTTE, N.C. -- Sweat poured from seemingly every inch of Ryan Kalil's 33-year-old body last week after what was the last minicamp practice of his NFL career.

"Can we stand in the shade?" the Carolina Panthers center asked as the temperature and humidity both soared into the 90s.

This time next year Kalil can stand in the shade all he wants. He is retiring following the 2018 season, his 12th since the Panthers selected him in the second round of the 2007 draft.

He made the decision this year after exhaustive talks with his family, former players such as Jake Delhomme and Jordan Gross, and former Carolina offensive line coach Ray Brown, who played 20 NFL seasons.

"Everybody sort of tells you you'll know when you know," Kalil said of when it's time to retire. "This feels right to me that this is the last one."

That doesn't mean Kalil believes his value to the team has diminished. He's in arguably his best shape since 2015 after being limited to six games last season because of a neck injury and 14 games over the past two seasons because of injuries.

He believes he can play to the level that's made him a five-time Pro Bowl selection, tied for the most in team history.

But as he approaches the final year of his contract and his production company in Los Angeles longs for more of his attention, Kalil figured this was the ideal time to call it quits.

"I had a long conversation with [Brown] about it," Kalil said. "It's a taxing job. That weighs a lot in on it. It's a fun job. It's a very fulfilling job. This place is an incredible work environment. I've gotten the chance to play with a lot of good, special people.

"So we're coming to the end, and I'm just enjoying every bit of it and honestly not really thinking about it other than I have to play well this season and help my team get back to the Super Bowl."

Hollywood future

Kalil began preparing for post-football life in 2016 when he and NBA star Blake Griffin formed the Los Angeles-based production company Mortal Media.

One of their first projects was co-producing the sequel to the 1991 Disney film "The Rocketeer." That year Kalil also co-wrote "The Rookie Handbook: How to Survive the First Season in the NFL."

"I try to be somewhat cultured," Kalil said at the time.

Kalil also worked with Dwayne "The Rock" Johnson on the movie "Son of Shaolin" and has been involved in a project to produce a remake of the 1992 hit "White Men Can't Jump."

But Kalil didn't fly to Los Angeles immediately after last week's mandatory minicamp to focus on his production company. He didn't even want to talk about his future in the movie business.

"Just focusing on football," Kalil said. "All my energy right now is on this offseason, getting as strong and fast as I can.

"There's a lot of hard-working people [with the production company] and I feel like a rookie and I'm enjoying that. But I haven't spent a lot of time doing that. It's tough doing that from here, and most of my focus -- all of my focus -- has been on professional football."

The past two seasons have been taxing on Kalil physically and mentally. He didn't sign a two-year, $16.75 million extension in 2016 to be a spectator or help groom his future replacement as the man who delivers the ball to quarterback Cam Newton.

"It was frustrating," Kalil said. "Obviously, a lot is expected of somebody in my position. I feel I didn't live up to that, regardless of how they compensate you, regardless of how the season turns out. For me, I take a lot of pride in doing my job and doing it the right way."

Participating in all of the offseason workouts and mandatory minicamp this year was important to Kalil on many fronts.

"The good thing for me is the team evaluated me in the offseason and how I played at the end of last year," he said. "We had a long discussion about going into this season. I felt and the team felt I could come and contribute and be at my best. I've gotten an opportunity this offseason to be evaluated at that point.

"I feel I've got enough for one more [season]. Give it a good run."

Matt Kalil (No. 75) and older brother Ryan spent the 2017 season with the Panthers -- their first season playing on the same football team. Ryan Kalil & Matt Kalil

Best memory not determined

Kalil was so excited about the 2012 season that he took out a full-page ad in the Charlotte Observer declaring the Panthers would win the Super Bowl.

They went 7-9.

Kalil has no plans to repeat that ad before this season, and he also has no shame about that prediction.

"Why would I regret that? Nothing bad happened," Kalil said with a laugh. "I'm not going to regret being overly excited and believing in my teammates. It's a fun game."

Kalil is not retiring because the fun is out of the game. In fact, he's enjoying it as much as ever -- particularly after the Panthers signed younger brother Matt Kalil last year to play left tackle.

It's the first time the brothers have been on the same team in their football careers, making Ryan's injury time last season all the more frustrating.

But Kalil doesn't want to stick around just to play longer with his brother. And he's not retiring because of any quibble with management over another contract extension.

"I've never asked for an extension since I've been here," Kalil said. "Most of my career I've treated every season like it's going to be my last. I've tried to do to the best of my ability to give the team the best I can give them and really play well on Sundays. It's worked out."

Kalil came close to winning the title in the 2015 season when the Panthers lost 24-10 to Denver in Super Bowl 50. That also was the fifth time Kalil was invited to the Pro Bowl.

But Kalil wouldn't say that season was the highlight of his career. He wouldn't commit to any highlight that could rank as the best moment.

"I don't know yet," he said. "When we get to the end, we'll get to the end. It could be this one."